Matched pair ECC802S - original Tesla production. Tubes were tested under following conditions: Uh= 12,6V, Ug1= -8,5V, Ua = 250V. Direct replacement for the american 12AU7 tubes. Will be delivered in modern white boxes - labels with measured parameters included. Electron tube ECC802S Tesla is a double triode of special quality with amplification factor 17, suitable for universal usage in low frequency amplifiers. High reliable tube, vibration and shock proof, tight tolerances and extra long life (over 10 000 operating hours). Year of production: 1965.